Im proven



N. FErERS, PHOTO LITHOGRAPHE UNITED "STATES lPATENT "Ornicia;

JOHN F.-SHEARMAN, OF BROOKLYN, NEW YORK.

Speciiicaton forming part of Letters Patent No. 54,968, dated May 22, 1866.

To all whom it may concern:

Be it known that I, JOHN F. SHEARMAN, ot' Brooklyn, E. D., in ihe county of Kings and State of New York, have invented, made, and

on the side of the chest, the exhaust passingw oft vertically.

Similar marks ot' reference denote the same parts.

In the ordin ary slide-valve the exhaust passes oft below the valve through a port formed in the valve-seat. In consequence ot' the tortuous passage through which the steam escapes much power is lost bythe back pressure, particularly in high speeds, in consequence of the steam not escaping freely from, the exhaust; besides this the valve is exposed to the pressure ot' the steam, greatly increasing its frietion on the seat. Y

Efforts have been made to relieve the valve from pressure of the steam by what are termed balanced valves, and the exhaust-port has has been increased in size to allow the steam freely to escape.

My invention combines a free and direct exhaust with the balancing of the valve; and it` consists in an exhaust -port passing through the valve, in combination with a cover and exhaust-pipe, whereby the steam is given a direct and enlarged exhaust, and the valve is relieved of a large portion of pressure from the steam.

In the drawings, a represents a portion of thesteam-cylinder. bandcarethesteam-ports, made in any usual manner. d is the steamchest, with any usual inlet or pipe for the steam, and e the cover of the steam-chest.

f is my improved valve, made with the portclosers l and 2, between which is an opening, 3, that passes through the valve.

l is the valve-rod, actuated in the usual way, so as to move the valve fat the proper time for admitting and exhausting the steam. The rod l passes through a hole in the valvef, and the exhaust-port 3 in said valve is bridged by a pipe, 4, through which the rod l passes.

g is the valve-cover, that passes through the cover c in the form ot' a pipe, connecting to the exhaust-pipe h and 'the stuffing box c' is provided around the pipeshaped portion of the cover g to keep the parts steam-tight.

I introduce a plate, k, in the form ot a ring, that rests upon a shoulder on g and receives the packing of the stuffing-box, the object of this ring being to prevent the packing in the stuffing-box becoming wedged between the cover g and the top otl the steam-chest. This ring or plate k might rest upon the top ofthe cover c within the stufing-box It will now be evident that as soon as the exhaust-port 3 comes over either ofthe steamports a direct and free escape is presented for the exhaust-steam, and that the space for the said exhaust can be much larger than can usually be introduced in the met-al between thecylinder and the valve-seat. The cover g to the valve also prevents steam-pressure from increasing the friction of the valve on its seat by removing the pressure or" steam from said valve to the extent of the area of the pipe .f/ 7L The cover g is kept tightly to the valve by the steam, as the area of the portion of the cover that is in contact with the valve is greater than the portion of the cover that passes as a pipe through the cover c.

The modification shown in Fig. 4 will be understood to consist in placing the cover g at one side ot the valve f instead of the top of the same. This will afford a direct passage for `the steam, but will not relieve the valve from the friction due to the pressure of steam.

As the valve or cover, or both, wear by use,

the parts will still remain steam-tight, because the stufling-box i around the pipe-shaped portion of said cover g allows that cover to move down to, and continue to rest upon, the valve as the parts wear.

In place of the'stufing-box i an expansion joint of any desired character may be employed with the cover g.

What' I claim, and desire to secure by Letters Patent, is-

1. The @over g,forming@termination to the exhaust-pipe h, Within the steam-chest, in oombination with lhe exhaust', port 3, passing` through the slide-valve, substantially as und for the purposes specified.

2. The arrangement of the exhaust-pipe h and cover g to the exhaust-port of the valve, and the expunsion-jointl or stuffing-box on the valve-chest around the exhaustpipe, as and for the purposes specified.

In witness whereof I have hereunto set my signature this 4th day of November, A. D. 1865.

JOHN F. SHEARMAN.

WVituesses:

GEO. D. WALKER, CHAs. H. SMITH. 

